403 - Forbidden Error

[Parthiban Narayanasamy]

We running 4 confluence server in clustering (data centre). users were not able to access the application and they have got 403 forbidden error. somehow the issue is resolved by restarting the services. 

error in at.log: datetime=2017-09-27 13:27:56,824 priority=ERROR thread=http-nio-8090-exec-910 category=rest.api.model.ExceptionConverter method=convertServiceException message=No status code found for exception, converting to internal server error : 

in cat.log: 27-Sep-2017 01:26:13.109 WARNING [ContainerBackgroundProcessor[StandardEngine[Standalone]]] org.apache.catalina.valves.StuckThreadDetectionValve.notifyStuckThreadDetected Thread "http-nio-8090-exec-841" 

anyone please assist me to identify the root cause? 

we are using confluence 5.10.8 server

[AnnWorley]

To find a root cause we will need to examine logs and other materials, so I opened a support ticket on your behalf. You should get an email from our portal shortly.

When your ticket is resolved, I will circle back to let the Community know what the issue turned out to be. 

[Parthiban Narayanasamy]

thanks for your response Ann. I have raised a ticket, number CSP-214021